Gear-shift forks of gearboxes



Dec. 6, 1960 L. PERAS GEAR-SHIFT FORKS OF GEARBOXES Filed May 11, 1959new 2,962,914 GEAR-SHIFT FORKS OF GEARBOXES Lucien Pras, Billancourt,Seine, France, assignor to Regle Natronale des Usines Renault,Billancourt, Seine, France, a French works Filed May 11, 1959, Ser. No.812,557 Claims priority, application France May 10, 1958 4 Claims. (Cl.74-477) This invention relates to forks of the type utilized forcontrolling the movements of sliding gears in gearboxes and the like,and has specific reference to a particularly simple and economicalstructure and construction of a two-fork arrangement applicable to thecontrol of two sliding gears or like members.

According to the essential feature of this invention, the two forks areof the type sliding on a fixed rod and consist of pressed and bentsheet-metal elements so as to form notably, in addition to thefork-shaped side controlling the sliding gear corresponding to each ofthem and when observing said forks in plane view, two opposed andinterengaging U portions slidably mounted by their outer arms on saidfixed rod, the inner arms of these U portions being formed withcorresponding pressed registering detent-positioning notches adapted toco-act with a single locking and safety device carried by the same rod.

In order to afford a clearer understanding of this invention and of themanner in which the same may be carried out in the practice, referencewill now be made to the accompanying drawing forming part of thisspecification and illustrating diagrammatically by way of example atypical form of embodiment thereof. In the drawing:

Figure 1 shows in elevational view taken in a direction at right anglesto the guide rod two forks mounted thereon;

Figure 2 is a plane view from above showing the arrangement of Fig. 1,and

Figure 3 is a cross-sectional view taken upon the line III-III of Fig.1.

In the drawing, the reference numerals 1 and 2 designate two forks ofpressed and bent sheet metal which are mounted according to thisinvention on a fixed rod 3.

As shown in Fig. 2 these two forks constitute two opposed interengagingU portions mounted for sliding movement on the rod 3 by means of theouter arms partially surrounding this rod and designated by thereference numerals 4 and 5, respectively. The central or inner arms ofthese U portions are each formed with three registering presseddetent-positioning notches 6 adapted to co-act with a single locking andsafety device 7 carried by the rod.

Each fork is formed with an opposite gear-engaging forked portion 8, 9adapted to co-act with the corresponding sliding gear or like member ofthe gearbox. These gear-engaging forks are conveniently co-extensivewith one arm of the U, the proper disposition being subordinate, as amatter of fact, to the position of the sliding gears or like members inthe gearbox.

Moreover, the central or inner arms of the aforesaid interengagingU-shaped portions are formed at their top with notched and bentregistering extensions providing together an aperture 10 adapted toreceive the driving end of a fork-actuating control lever (not shown).

As will be readily understood, the locking and safety device 7 consistssimply of a pair of opposite springloaded bolts 11 slidably mounted in aguide sleeve 12 fitted in a transverse bore of the rod 3, these boltsbeing urged against the detent positioning notches 6 by a common centralcompression spring 13.

2,962,914 Patented Dec. 6, 1960 The safety feature, which consists inpreventing the two forks from moving simultaneously in case of improperpositioning of the control lever (not shown) engaging the aforesaidaperture 10, is obtained by forming the spring-loaded bolts 11 with suchaxial dimensions that their combined length exceeds that affording thesimultaneous clearing of the ridges 14 separating ad jacent notches 6 bythese bolts; in other words, this length must be greater than thedistance 15 measured between a pair of registering ridges 14 across therod 3.

The safety obtained against the untimely or undesired displacement of afork member either as a consequence of the inertia of the sliding gear,or for any other reason, while the other fork is in a speed-engagingposition, results from a difference in depth between the central notch 6and the lateral notches, the former being deeper than the latter. Thus,for example, assuming that the fork 9 has been moved to a positioncorresponding to the engagement of a relevant gear, one end notch 6 willregister with the locking and safety device 7 and the distance measuredbetween the inner faces of the springloaded bolts is therefore inferiorto that existing between the bottom of the opposite notch 6 and theridges 14, whereby the other forks 8 is safely held against movement.

In addition to the action resulting from the presence of thisdetent-positioning and safety device, the forks are also maintained intheir proper relative positions about the rod 3 by the engagement oftheir fork-shaped portions 8 with the relevant sliding gear or likemember.

I claim:

1. A gearbox fork arrangement for controlling two sliding gearscomprising a stationary rod, a pair of forks mounted to slide axially onthe rod and having gear engaging projecting portions, said forks beingformed from pressed and bent sheet metal and including opposedinterengaging U-shaped portions, each portion having outer arms slidablymounted on the rod and inner arms having inner opposing faces formedwith corresponding pressed, registering detent-positioning notches and asingle locking and safety device carried by the rod with which thenotches coact.

2. A gearbox fork arrangement as defined in claim 1, wherein the innerarms are formed at their top with notched and bent registeringextensions forming together an aperture adapted to receive the drivingend of a forkactuating control lever.

3. A gearbox fork arrangement as defined in claim 1, wherein saidlocking and safety device consists of a pair of opposed spring-loadedbolts slidably mounted in said rod and extending radially therefrom andurged for engagement with the detent-positioning notches by a commonspring interposed between said bolts, the axial dimensions of said boltsbeing such that their combined length exceeds that affording thesimultaneous clearing by these bolts of the opposite ridges thatseparate the adjacent detent-positioning notches.

4. A gearbox fork arrangement as defined in claim 3, whereby anyundesired displacement of one fork while the other fork is in the propergear engaging position is prevented by forming the end notches with adepth less than that of the intermediate notch whereby the distancemeasured between the inner faces and the springloaded bolts is less thandepth of the intermediate notches.

References Cited in the file of this patent UNITED STATES PATENTS Re.14,052 Johnson Jan. 25, 1916 1,309,852 Jensen July 15, 1919 1,377,331Ford May 10, 1921 2,168,592 Vanderveld Aug. 8, 1939

